Engines such as, Direct Injected Gas (DIG) engines employ direct injection of fuel at high pressure into a cylinder for combustion. The fuel used may be a combination of two fuels, such as natural gas and diesel, in the ratio of up to 99:1. The two fuels may be directly injected into the cylinder when an intake valve thereof may be closed. In such a situation, diesel may serve as a pilot fuel for ignition of the natural gas within the cylinder.
Due to the direct injection of the fuel within the cylinder, time available for adequate mixing of the fuel with air present within the cylinder may be limited. As a result, the mixing of the fuel and the air may remain localized and/or non-homogenized within the cylinder. This in turn may result in incomplete combustion of the fuel within the cylinder. The incomplete combustion may further result in reduced overall engine efficiency, increased maintenance schedules, increased emissions such as Particulate Matter (PM), unburned Hydrocarbon (HC), and so on.
U.S. Published Application Number 2015/0107543 describes a piston for an internal combustion engine. The piston includes a piston skirt with a center axis. The piston includes a piston crown disposed adjacent a top of the piston skirt. The piston crown includes a diameter D. The piston crown includes a piston crown margin of width b extending in a circumferential direction. The piston crown also includes a piston trough with a depth t. The piston trough further includes a piston trough wall with a base diameter. The piston trough includes at least one recess with a height h. The height h parallel to a direction of the center axis satisfies the requirement: 0.2 t<=h<=t.